FRGM_METHOD

Specifies a locally-projected method.

TYPE:

STRING

DEFAULT:

NONE

OPTIONS:

STOLL

Locally-projected SCF equations of Stoll are solved.

GIA

Locally-projected SCF equations of Gianinetti are solved.

NOSCF_RS

Single Roothaan-step correction to the FRAGMO initial guess.

NOSCF_ARS

Approximate single Roothaan-step correction to the FRAGMO initial guess.

NOSCF_DRS

Double Roothaan-step correction to the FRAGMO initial guess.

NOSCF_RS_FOCK

Non-converged SCF energy of the single Roothaan-step MOs.

RECOMMENDATION:

STOLL and GIA are for variational optimization of the ALMOs. NOSCF options are for computationally fast corrections of the FRAGMO initial guess.

FRGM_LPCORR

Specifies a correction method performed after the locally-projected equations are converged.

TYPE:

STRING

DEFAULT:

NONE

OPTIONS:

ARS

Approximate Roothaan-step perturbative correction.

RS

Single Roothaan-step perturbative correction.

EXACT_SCF

Full SCF variational correction.

ARS_EXACT_SCF

Both ARS and EXACT_SCF in a single job.

RS_EXACT_SCF

Both RS and EXACT_SCF in a single job.

RECOMMENDATION:

For large basis sets use ARS, use RS if ARS fails.

SCF_PRINT_FRGM

Controls the output of Q-Chem jobs on isolated fragments.

TYPE:

LOGICAL

DEFAULT:

FALSE

OPTIONS:

TRUE

The output is printed to the parent job output file.

FALSE

The output is not printed.

RECOMMENDATION:

Use TRUE if details about isolated fragments are important.

EDA_BSSE

Calculates the BSSE correction when performing the energy decomposition analysis.

TYPE:

LOGICAL

DEFAULT:

FALSE

OPTIONS:

TRUE/FALSE

RECOMMENDATION:

Set to TRUE unless a very large basis set is used.

EDA_COVP

Perform COVP analysis when evaluating the RS or ARS charge-transfer correction. COVP analysis is currently implemented only for systems of two fragments.

TYPE:

LOGICAL

DEFAULT:

FALSE

OPTIONS:

TRUE/FALSE

RECOMMENDATION:

Set to TRUE to perform COVP analysis in an EDA or SCF MI(RS) job.

EDA_PRINT_COVP

Replace the final MOs with the CVOP orbitals in the end of the run.

TYPE:

LOGICAL

DEFAULT:

FALSE

OPTIONS:

TRUE/FALSE

RECOMMENDATION:

Set to TRUE to print COVP orbitals instead of conventional MOs.

NVO_LIN_MAX_ITE

Maximum number of iterations in the preconditioned conjugate gradient solver of the single-excitation amplitude equations.

TYPE:

INTEGER

DEFAULT:

30

OPTIONS:

User–defined number of iterations.

RECOMMENDATION:

None.

NVO_LIN_CONVERGENCE

Target error factor in the preconditioned conjugate gradient solver of the single-excitation amplitude equations.

TYPE:

INTEGER

DEFAULT:

3

OPTIONS:

User–defined number.

RECOMMENDATION:

Solution of the single-excitation amplitude equations is considered converged if the maximum residual is less than multiplied by the current DIIS error. For the ARS correction, is automatically set to 1 since the locally-projected DIIS error is normally several orders of magnitude smaller than the full DIIS error.

NVO_METHOD

Sets method to be used to converge solution of the single-excitation amplitude equations.

TYPE:

INTEGER

DEFAULT:

9

OPTIONS:

User–defined number.

RECOMMENDATION:

Experimental option. Use default.

NVO_UVV_PRECISION

Controls convergence of the Taylor series when calculating the block from the single-excitation amplitudes. Series is considered converged when the maximum element of the term is less than .

TYPE:

INTEGER

DEFAULT:

11

OPTIONS:

User–defined number.

RECOMMENDATION:

NVO_UVV_PRECISION must be the same as or larger than THRESH.

NVO_UVV_MAXPWR

Controls convergence of the Taylor series when calculating the block from the single-excitation amplitudes. If the series is not converged at the th term, more expensive direct inversion is used to calculate the block.

TYPE:

INTEGER

DEFAULT:

10

OPTIONS:

User–defined number.

RECOMMENDATION:

None.

NVO_TRUNCATE_DIST

Specifies which atomic blocks of the Fock matrix are used to construct the preconditioner.

TYPE:

INTEGER

DEFAULT:

-1

OPTIONS:

If distance between a pair of atoms is more than angstroms

do not include the atomic block.

-2

Do not use distance threshold, use NVO_TRUNCATE_PRECOND instead.

-1

Include all blocks.

0

Include diagonal blocks only.

RECOMMENDATION:

This option does not affect the final result. However, it affects the rate of the PCG algorithm convergence. For small systems use default.

NVO_TRUNCATE_PRECOND

Specifies which atomic blocks of the Fock matrix are used to construct the preconditioner. This variable is used only if NVO_TRUNCATE_DIST is set to .

TYPE:

INTEGER

DEFAULT:

2

OPTIONS:

If the maximum element in an atomic block is less than do not include

the block.

RECOMMENDATION:

Use default. Increasing improves convergence of the PCG algorithm but overall may slow down calculations.